Differential Use of Fe3+ and Fe2+ by Oats1
- J. C. Brown
Plants have specific Fe requirements, dependent on their ability to make Fe available in a useful form. They are classed Feefficient if they respond to Fedeficiency stress by inducing biochemical reactions that make Fe available in a useful form, and Fe-inefficient if they do not. This study was conducted to characterize the use of Fe by Feinefficient oats (Avena byzantina K. Koch) ‘TAM 0-312,’ and Fe-efficient oats ‘Coker 227.’ These cultivars were grown in nutrient solutions where they were subjected to different degrees of Fe stress induced by variable concentrations of either phosphate, CaCO3, or Fe. The oat plants were grown in an environmentally-controlled chamber with 16 hours of light at approximately 320 µEm-3 sec-l and 8 hours of darkness at a temperature of 24 ± 2 C. Coker 227 was more Fe-efficient than TAM 0-312 regardless of how Fe stress was induced and usually contained less Ca than TAM 0-312. TAM 0.312 required 1.2 mg Fe/liter in the nutrient solution before it was green, whereas Coker 227 required only 0.6 mg Fe/liter. Susceptibility to Fe chlorosis in these cultivars was caused by the inherent nature of the plant to use either Fe8+ or F2+ and by the greater use of Ca by TAM 0-312 than by Coker 227. The plant plays a key role in maintaining a proper nutrient elememt balance and the availability of a nutrient element for plant use.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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